A proposed $20 million bicycle bridge over Highway 101 again appears in peril after Santa Rosa council members raised new questions about the cash-strapped city's ability to afford the soaring cost of the controversial project.

To some it's a vital link for bicyclists and pedestrians between Santa Rosa Junior College and Coddingtown Mall neighborhoods, one that will create construction jobs and reduce greenhouse gases.

To others it's an expensive pet project the city can ill-afford given its current budget crunch, the need to maintain pothole-pocked roads and uncertainty about the arrival of a second Santa Rosa rail station.

But to City Councilman Scott Bartley, the prospect of cost increases when the project is still in its infancy was difficult to stomach.

"I'm getting a little heartburn over something going from $200,000 to (another) $300,000 in four months," Bartley said during Thursday's budget meeting.

Bartley and fellow Councilman Jake Ours questioned the rising costs of a key Caltrans study of the project, which is three years away from construction at the earliest.

Initially expected to cost $200,000, the new study — called a project initiation document — is now expected to top $500,000, council members learned.

Caltrans informed the city that the state budget crisis has forced it to push more costs back onto the city, said Colleen Ferguson, deputy director of public works. Caltrans now estimates its costs to participate in the study at $150,000, while the city's consultant, Berkeley-based Steven Grover & Associates, has estimated higher than expected costs at $250,000.

"It is much more than we had originally anticipated," Ferguson said.

The city has spent more than $150,000 to date on a feasibility study, which envisions a curvaceous 15-foot-wide span from Elliott Avenue on the east side of Highway 101 to Edwards Avenue on the west. The precise design and layout would be determined later after negotiations with property owners and community meetings.

"This is a really important project, I think, for Santa Rosa and for Sonoma County," said Christine Culver, a project manager with the Sonoma County Bicycle Coalition.

The bridge would let more people bike and walk, with all the associated health benefits and greenhouse gas reductions. It would also support ridership at the Sonoma-Marin Area Rail Transit's proposed station at Guerneville Road. And the bridge would offer an alternative to intersections like the Steele Lane undercrossing, which Culver called "thoroughly nasty" for bikers and pedestrians alike.

But the $300,000 surprise didn't sit well with Ours, who said he was concerned about the cost increase and wanted a list of other projects the city council might spend the gas tax money on.

Bartley agreed. "It's a good project, but if that's the cost, right now maybe there's a more prudent place to spend that money," Bartley said.

The council didn't vote on the issue Thursday. The comments came during a review of the city's $13 million capital improvement budget, which will return to the council for public hearings in mid-June.

But the remarks by Ours and Bartley were significant because they echoed comments made late last year by council allies Mayor Ernesto Olivares and John Sawyer. Together the four, who have the backing of most of the city's business groups, represent the new council majority.

After airing his concerns about funding the project during a meeting in late November, Sawyer threatened to block $100,000 in funding for the Caltrans study once the new majority came to power.

Sawyer said the timing of the project, while a good one, wasn't right in part because the location for the second Santa Rosa SMART station had not been formalized. Olivares voted against the project for similar reasons.

But some shrewd parliamentary maneuvering by former Mayor Susan Gorin and her allies parried Sawyer's threat at a meeting in December and the $100,000 was preserved.

If the money for the study were removed from the budget next year, Ferguson told the council that the city would lose the $100,000 grant it had already received for the work.

Councilmember Marsha Vas Dupre also noted that Santa Rosa Junior College has agreed to spend $1 million toward the project. The reference was to a settlement between the college and the Sonoma County Bicycle Coalition, which sued over the use of funds for the construction of a multi-story parking garage in front of Bailey Field.

But that $1 million offer may have already left the station. The settlement requires the city to commit to construction by the end of 2012, a deadline that would appear impossible given Ferguson's estimate of 18 to 24 months to complete the Caltrans study before environmental work could begin.

Gorin, in an email to supporters, said the opposition now expressed by the four members of the majority means the project "will be effectively killed or delayed for a long time," adding "now is the time for advocacy and organization."